Watts Benchmark Aerco OMM-0122 - Page 47

Benchmark 750-3000 Boiler Installation & Startup Manual
SECTION 3 - START SEQUENCE
OMM-0121_D • GF-205 • 5/9/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 47 of 122
Start Sequence
Figure 3-1c: BMK 2500: SSOV Location
Figure 3-1d: BMK 3000: SSOV Location
3.
With all required safety device switches closed, a purge cycle will be initiated and the
following events will occur:
a. The Blower relay energizes and turns on the blower.
b. The Air/Fuel Valve rotates to the full-
open purge position and closes purge position
switch. The dial on the Air/Fuel Valve (Figure 3-2a and 3-2b) will read 100 to indicate
that it is full-open (100%).
c. The VALVE POSITION bargraph will show 100%.
TO
AIR/FUEL
VALVE
MANUAL
SHUT-OFF
VALVE
LOW GAS
PRESSURE
SWITCH
SSOV
SSOV
TO
AIR/FUEL
VALVE
NATURAL
GAS INLET
HIGH GAS PRESSURE
SWITCH
MANUAL
SHUT-OFF VALVE
LOW GAS
PRESSURE
SWITCH
NATURAL
GAS INLET